Calling functions that have a variable name

I have a set of functions that have the general naming scheme of: function%d_%d. They all have the same input and I want to call them within two loops (for example a loop for variable n and another for k, meaning calling for functionn_k). Is it possible to do so and how?

[Daniel Cohen]

To make it clearer, the functions are generated from a script for some symbolic computations using matlabFuntion to generate said functions. This is done within a loop, with each iteration referring to some potential coefficient and potential function, this is why the generated functions are named (essentially as) functionn_k.

[Stephen23]

"...the generated functions are named (essentially as) functionn_k."

How exactly? Are you writing them as function files (Mfiles) or as variables in the workspace or something else?

[Daniel Cohen]

I have a function that produces using MATLAB symbolic the potential function of some gravitational field. This potential can be addressed based on the order of the potential field (Look up the geopotential model in wiki, I am addressing here for example the J2 J3... fields).

And so, by having a function that computes the field potential symbolicly, I can have the function matlabFunction convert it into actual MATLAB function that are saved as Mfiles.

Answer 1

[Matt J]

Just generate handles to all the functions. Then they can be used freely to make function calls, e.g.,

F=cellfun(@str2func,  compose('function%d_%d',(1:3)',1:5),      'uni',0) 

F = 3×5 cell array
    {@function1_1}    {@function1_2}    {@function1_3}    {@function1_4}    {@function1_5}
    {@function2_1}    {@function2_2}    {@function2_3}    {@function2_4}    {@function2_5}
    {@function3_1}    {@function3_2}    {@function3_3}    {@function3_4}    {@function3_5}

for i=2,
    for j=3,
        y=F{i,j}(5)
    end
end

y = 50

function y=function2_3(x)
  y=10*x;
end

[Walter Roberson]

str2func is probably the best approach for this.

You could also use feval but it would not be as efficient.

[Daniel Cohen]

Thank you, str2func is exactly the solution I was looking for!

Answer 2

[Catalytic]

That sounds like a bad idea. You should probably make a single function where (n,k) are one of the arguments -

function oneFunction(n,k,other_arguments)

end